In the case of the cassette mode of construction of the intermediate roll sets for 18 HS roll stands, pivotable cluster arms—in which the lateral backing rolls for support of the slender working rolls in the stand are integrated—are arranged between the chock at the operating side and the chock at the drive side to be pivotable laterally of the intermediate roll (inlet side and outlet side). The purpose of the backing rolls integrated in the cluster arms is to prevent warping of the working roll as well as to realize the horizontal offset (HS) of the working roll with respect to the intermediate roll with the help of the support bridge adjustment arranged therebehind.
In the case of a roll change, when with support bridge adjustment into a retracted setting the cluster arms ‘are free’, the cluster arms have to be brought into a defined position and be disposed centrally with respect to the stand and thus position the working rolls on the stand center.
In known constructions the pivot axle, which is fixedly connected with the cluster arm, is led completely through the chocks as far as the outer side thereof and fixed by retaining blocks, so that the axle can rotate in the chocks. Restoring of the cluster arms to the defined ‘center position’ is realized in that the pivot axle, which protrudes through the chock, of the cluster arm presses the cluster arm into the desired position by way of spring packets. This arrangement requires increased effort for the assembly and servicing of the intermediate roll set together with the cluster arms, since removal of the retaining blocks and the spring packets on each occasion of demounting and remounting the retaining blocks and spring packets, as well as setting of the spring packets for establishing the central position of the cluster arms, are necessary in the roll workshop.
In addition, in order to demount the cluster arm the two chocks have to be completely moved apart until the long pivot axle is free.